In integrated Gasification Combined Cycle Power Plants, fuel gas for use in the gas turbine is produced at high pressure and high temperature in the gasification unit. The fuel gas produced by the gasification process unit, known as syngas, contains particulate matter and other harmful contaminants which must be removed to very low levels prior to use as fuel in the combustor of the gas turbine. In order to improve efficiency, many gasification power plants recover heat from the dirty syngas by heating hot water to steam and/or by heating clean fuel gas. However, due to the corrosive and erosive nature of dirty syngas in heat recovery heat exchangers, such heat recovery units are prone to developing leaks with the result that dirty syngas can mix with clean fuel gas, causing heavy damage and potentially resulting in failure of the gas turbine.